Slide rules comprising an upper cover plate, a lower cover plate, side guide members and a slide positioned between the cover plates and the guide members are known. With a known method for producing such slide-rules, the guide members are glued to the lower cover plate. Thereafter the upper cover plate is glued to the guide members and the structure, in which the slide is guided, is thus obtained. Even though resulting in a simple construction of the slide-rule, this construction requires some time and still, since in order to maintain parallelism of the guide members and keep the exact required distance of the same, special gauge means are necessary when connecting the guide members to the cover plates. It is also known to construct slide-rules by cutting two parallel lines with a knife or the like into a card board plate; the cutting lines thereby do not fully separate the plate. Thereafter, the plate is connected to an upper and a lower cover plate and the boundary areas, which include the portions still connecting the guide members and slide, are cut off.
With this type of production, no adjustment steps or means are necessary; however, by the cutting action oblique surfaces with burs are generated. Some material along these obliquely cut edges is displaced and results in a bow or vault along the edges. It is not possible to obtain rectangularly cut surfaces opposing each other as required for accurate sliding of the slide on the surfaces of the guide members. The parallelism of the guide surfaces isn't accurate enough. As a consequence of the obliqueness of the side surfaces - especially when the slides are of broader width - a danger exists that the slide slips or moves between the guide members and the cover plates. This means that the guidance of the slide and the accuracy of reading the scales on the cover plates is largely deteriorated. Further, with this procedure one can only produce slide-rules of paper board. If the mentioned process is applied to plastic foil or sheets, the bows or vaults generated by the displacement of material along the cutting edges will become too large.
A further procedure is known from German Pat. No. 22 54 387. It provides that the cover plates are connected between two connecting rails, which serve as guide members and which are generally E-shaped. The middle flanges at the E-shaped rail serve as the guides of the slide. This method provides precisely guided slides; however, it requires a certain effort during production and therefore is too time consuming.